Capsular polysaccharides from enterococci

Abstract

The present invention is directed to a method for purifying polysaccharides capable of inducing the production of high titers of opsonic antibodies that kill strains of enterococcal bacteria. In addition, the invention is directed to the antigens produced by this purification method and to vaccines which utilize such antigens.

What is claimed is: 
     
       1. A substantially purified bacterial polysaccharide, comprising a repeating disaccharide unit with a structure of 6-α-D-GlcP-α-1→2[(2→1)-α-D-GlcP]-glycerol(PO 4 ) 2  -3→, said disaccharide being linked to a glycerol teichoic acid backbone via the number 2 carbon of glycerol and wherein there are phosphodiester bonds between the first carbon of the glycerol backbone and the sixth carbon of said glucose disaccharide. 
     
     
       2. A vaccine comprising the polysaccharide of claim 1. 
     
     
       3. An isolated immunogenic polysaccharide comprising the structure: ##STR1## . 
     
     
       4. The immunogenic polysaccharide of claim 3, wherein said polysaccharide has been purified from E. faecalis. 
     
     
       5. The immunogenic polysaccharide of claim 4, wherein said polysaccharide has been isolated by a process comprising the steps of: a) digesting E. faecalis bacteria with mutanolysin/lysozyme, nucleases, and pronase E;   b) size fractionating the digestion product of step a) by column chromatography; and   c) selecting those fractions containing said immunogenic polysaccharide.   
     
     
       6. A vaccine comprising the polysaccharide of any one of claims 3-5, wherein said polysaccharide has been purified to remove teichoic acids.